Effect of helium breathing on cardiac arrhythmias induced by coronary occlusion and digitalis in the cat
Evans, D.E.; Hardenbergh, E.; Raymond, L.W.; Bradley, M.E.
Undersea Biomedical Research 4(4): 381-389
1977
ISSN/ISBN: 0093-5387 PMID: 601909 Document Number: 116569
This study assessed the capacity of He breathing to antagonize cardiac arrhythmias induced by either coronary occlusion or digitalis intoxication in the cat. Animals were anesthetized with chloralose, immobilized with succinylcholine, and ventilated to maintain arterial blood gases and pH within normal physiological limits. Animals subjected to acute ligation of the anterior descending coronary artery were ventilated with either air or He-O2 begun 15 min before occlusion. In each group, approximately 30% of the animals died from ventricular fibrillation within 5 min after coronary occlusion. In animals that survived this period, those ventilated with He-O2 exhibited significantly more premature ventricular beats during 1 h after coronary occlusion than did animals ventilated with air. In a separate series of experiments, cats were infused with deslanoside and the doses required to cause arrhythmias and death were determined. These animals were ventilated with either air, He-O2 or nitrous arrhythmias and death induced by digitalis intoxication. No evidence was found for an antiarrhythmic effect of He breathing against 2 types of experimentally induced arrhythmias in the chloralose-anesthetized cat. Under certain circumstances He breathing may have the opposite effect.